Various adaptive filter structures have been developed for use in time updated adaptive systems to solve acoustical echo cancellation, line echo cancellation, channel equalization and other problems; examples of such structures include for example, transversal, multistage lattice, systolic array, and recursive implementations. Among these, transversal finite-impulse-response (FIR) filters are often used, due to stability considerations, and to their versatility and ease of implementation. Many algorithms have also been developed to adapt these filters, including the least-mean-square (LMS), recursive least-squares, sequential regression, and least-squares lattice algorithms.
A deficiency with the FIR filters commonly being used for echo-cancellation is that they do not easily remove echo in the presence of double-talk. Double-talk occurs when two entities in a communication exchange talk at the same time. In the absence of double talk, the entire signal can be removed and replaced by comfort noise and/or background noise. However in the presence of double talk, it is desirable to remove the echo component without substantially affecting the non-echo signal.
Consequently, there is a need in the industry for providing a method and apparatus for use in reducing echo in a communication system that alleviate at least in part the deficiencies of the prior art.